Monitoring of enzymatic enantioselective acetylation of gem-difluorinated alcohols by capillary electrophoresis
Šolínová, Veronika; Pomeisl, Karel; Lamatová, Nikola; Pohl, Radek; Brabcová, Jana; Krečmerová, Marcela; Kašička, Václav
2018 - English
A new fast and highly efficient capillary electrophoretic (CE) method has been developed for chiral analysis of non-charged gem-difluorinated alcohol (3-(benzyloxy)-1,1-difluoro-propan-2-ol) using sulfobutylether-β-CD as chiral selector. The method was applied for monitoring of enzymatic (lipase mediated) enantioselective acetylation of the above alcohol and for determination of enantiomeric purity of both substrates and products of the enzymatic reaction.
Keywords:
enantioselective acetylation; difluorinated alcohols; capillary electrophoresisAvailable at various institutes of the ASCRMonitoring of enzymatic enantioselective acetylation of gem-difluorinated alcohols by capillary electrophoresis

A new fast and highly efficient capillary electrophoretic (CE) method has been developed for chiral analysis of non-charged gem-difluorinated alcohol (3-(benzyloxy)-1,1-difluoro-propan-2-ol) using ...

Affinity capillary electrophoresis applied to chiral separations of diquats and to determination of the stability constants of their complexes with sulfated cyclodextrins
Kašička, Václav; Bílek, Jan; Koval, Dušan; Sázelová, Petra; Talele, Harish Ramesh; Severa, Lukáš; Reyes Gutierrez, Paul Eduardo; Teplý, Filip
2018 - English
Affinity capillary electrophoresis (ACE) using an aqueous 22/35 mM sodium/phosphate buffer, pH 2.5, as the background electrolyte (BGE), and 6 mM randomly highly sulfated alpha-, beta- and gamma-cyclodextrins (CDs) as chiral selectors has been successfully applied for separation of (P)- and (M)-enantiomers of a series of eleven new diquats (DQs) and for estimation of the strength of their complexes with the above CDs. The apparent stability constants of the DQs-CDs complexes were determined from the simultaneous ACE measurements of the dependence of effective electrophoretic mobilities of (P)- and (M)-enantiomers of DQs on the concentrations of CDs in the BGE by nonlinear regression analysis. The DQs enantiomers formed strong complexes with all three types of CDs with the apparent stability constants in the range (7.80 547.4) × 103 L/mol.
Keywords:
affinity capillary electrophoresis; chiral separations; diquatsAvailable at various institutes of the ASCRAffinity capillary electrophoresis applied to chiral separations of diquats and to determination of the stability constants of their complexes with sulfated cyclodextrins

Determination of stability constants of antamanide complexes with sodium and potassium ions by affinity capillary electrophoresis
Pangavhane, Sachin; Böhm, S.; Makrlík, E.; Ruzza, P.; Kašička, Václav
2018 - English
Affinity capillary electrophoresis (ACE) was applied for quantitative investigation of the interactions between important biomolecule, cyclic decapeptide antamanide (AA), cycl[-Val(1)-Pro(2)-Pro(3)-Ala(4)-Phe(5)-Phe(6)-Pro(7)-Pro(8)-Phe(9)-Phe(10)-], and sodium and potassium cations in methanol. Apparent stability constants of AA complexes with these alkali metal ions were determined from the dependence of effective mobility of AA on the concentration of these ions in the background electrolyte by the non-linear regression analysis. The AA complexes with Na+ and K+ ions were found to be relatively weak, with the apparent stability constants 343 L/mol and 35 L/mol, respectively.
Keywords:
affinity capillary electrophoresis; antamanide; binding constantAvailable at various institutes of the ASCRDetermination of stability constants of antamanide complexes with sodium and potassium ions by affinity capillary electrophoresis

Affinity capillary electrophoresis (ACE) was applied for quantitative investigation of the interactions between important biomolecule, cyclic decapeptide antamanide (AA), ...

Separation of rotamers of 5-nitrosopyrimidines by capillary electrophoresis
Štěpánová, Sille; Procházková, Eliška; Čechová, Lucie; Žurek, Jiří; Janeba, Zlatko; Dračínský, Martin; Kašička, Václav
2018 - English
A new capillary electrophoresis (CE) method was developed for the separation of a new type of stereoisomers - rotamers of polysubstituted 5-nitrosopyrimidine derivatives. Partial separation of some rotamers was obtained in sodium borate, pH 9.3, or in Tris-phosphate, pH 2.2, background electrolytes (BGEs) free of cyclodextrins (CDs). However, the best, baseline separations of the rotamers of 5-nitrosopyrimidines were achieved in sodium borate BGE, pH 9.3, containing 20 mg/mL beta-CD as stereoselector, or in Tris-phosphate BGE, pH 2.2, with carboxymethyl-beta-CD as stereoselector.
Keywords:
rotamers; 5-nitrosopyrimidines; capillary electrophoresisAvailable at various institutes of the ASCRSeparation of rotamers of 5-nitrosopyrimidines by capillary electrophoresis

A new capillary electrophoresis (CE) method was developed for the separation of a new type of stereoisomers - rotamers of polysubstituted 5-nitrosopyrimidine derivatives. Partial separation of some ...

Ambientní ionizační techniky
Vrkoslav, Vladimír
2018 - Czech
V první část přednášky se zabývá vymezením pojmu ambientních ionizačních technika a rozdělením těchto technik. V další části byly vysvětleny principy nejdůležitějších ambientních ionizačních technika a bylo popsáno jejich využití.In the first part of the lecture definition and classification of ambient ionization techniques were described. In the next part the principles of the most important ambient ionization techniques were explained and their use was mentioned.
Keywords:
mass spectrometryAvailable at various institutes of the ASCRAmbientní ionizační techniky

Enantioseparation and estimation of racemization barriers of selected helquats and their derivatives by capillary electrophoresis using sulfated cyclodextrins as chiral selectors
Sázelová, Petra; Koval, Dušan; Severa, Lukáš; Reyes Gutierrez, Paul Eduardo; Jirásek, Michael; Teplý, Filip; Kašička, Václav
2018 - English
Anionic highly sulfated β- and γ-cyclodextrins (S-CDs) and single-isomer heptakis-(2,3-diacetyl-6-sulfato)-β-CD (14Ac-7S-β-CD) were used for chiral separation of [5], [6] and [7]-ring helquats and helquat styryl dyes by capillary electrophoresis (CE) in the background electrolyte composed of 22 mM NaOH/35 mM H3PO4, pH 2.4. The CE method was applied for monitoring of racemization of eight helquats and helical dyes. Rate constant k of conversion, half-life T1/2 of racemization, and activation Gibbs free energy ΔGǂ of interconversion of one enantiomer into the other were calculated from the dependence of natural logarithm of enantiomeric excess (ee) on time using linear regression analysis.
Keywords:
helquats; racemization barrier; capillary electrophoresisFulltext is available at external website.Enantioseparation and estimation of racemization barriers of selected helquats and their derivatives by capillary electrophoresis using sulfated cyclodextrins as chiral selectors

Anionic highly sulfated β- and γ-cyclodextrins (S-CDs) and single-isomer heptakis-(2,3-diacetyl-6-sulfato)-β-CD (14Ac-7S-β-CD) were used for chiral separation of [5], [6] and [7]-ring helquats and ...

Determination of Bitrex in conifer needles using capillary electrophoresis
Jaklová Dytrtová, Jana; Jakl, M.; Konášová, Renáta; Kašička, Václav
2018 - English
Two extraction procedures have been developed for the sample preparation regarding the determination of Bitrex (Denatonium benzoate) on the surface of conifer needles (1) and in the biomass of the chopped conifer needles (2). The content of the Bitrex in the extracts was determined by capillary electrophoresis with UV-absorption photometric detection. The recovery of Bitrex from the needle surface is 90%, however the procedure designed for determination of Bitrex from needles is not sufficient, because the recovery is only 30 %.
Keywords:
denatonium benzoate; needle extracts; capillary electrophoresisAvailable at various institutes of the ASCRDetermination of Bitrex in conifer needles using capillary electrophoresis

Two extraction procedures have been developed for the sample preparation regarding the determination of Bitrex (Denatonium benzoate) on the surface of conifer needles (1) and in the biomass of the ...

Estimation of binding constants of associates of Ru(II) and Fe(II) polypyridyl complexes with single-isomer sulfated cyclodextrins by capillary electrophoresis
Sázelová, Petra; Koval, Dušan; Severa, Lukáš; Teplý, Filip; Kašička, Václav
2018 - English
Capillary electrophoresis (CE) was applied for enantioseparations of [Ru(bpy)3]2+, [Ru(phen) 3]2+ and [Fe(phen) 3]2+ complexes and for the estimation of binding constants of their associates with selected single-isomer sulfated cyclodextrins (SCDs). The apparent binding constants of the complexes of [Ru(bpy)3]2+, [Ru(phen)3]2+, and [Fe(phen)3]2+ enantiomers with the above SCDs were determined from the dependence of their effective electrophoretic mobilities on the concentration of the SCDs in the background electrolyte. Calculated apparent binding constants were found to be smaller than those obtained for randomly sulfated SCDs.
Keywords:
polypyridyl complexes; stability constant; capillary electrophoresisAvailable at various institutes of the ASCREstimation of binding constants of associates of Ru(II) and Fe(II) polypyridyl complexes with single-isomer sulfated cyclodextrins by capillary electrophoresis

Capillary electrophoresis (CE) was applied for enantioseparations of [Ru(bpy)3]2+, [Ru(phen) 3]2+ and [Fe(phen) 3]2+ complexes and for the estimation of binding constants of their associates with ...

Penconazole and its behaviour in the presence of copper
Jakl, M.; Jaklová Dytrtová, Jana
2018 - English
Penconazole is a fungicide frequently used in agriculture. Its possible impact to (non-)target species is influenced by its interactions e.g. with copper, typically present in soil as an ion (or in week complexes) or in bodies, as a part of enzymes. This study brings the information potentially useful in the evaluation of penconazole fate in the environment. The studies based on the electrospray gas phase experiments provide an estimate of the penconazole reactivity in copper presence including its possible degradation pathways.
Keywords:
triazoles; Cu(II); Cu(I); mass spectrometry; ESI-MS; stability; degradationAvailable at various institutes of the ASCRPenconazole and its behaviour in the presence of copper

Penconazole is a fungicide frequently used in agriculture. Its possible impact to (non-)target species is influenced by its interactions e.g. with copper, typically present in soil as an ion (or in ...

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